Electroanalytical Studies of Transport Phenomena and Electrostatic Interactions in Polyacrylate Gels

摘要

The transport of uncharged electroactive probes, 1,1'- ferrocenedimethanol and 4-hydroxy-TEMPO, and electroactive cations, Tl(+), was studied in polyacrylate hydrogels using steady-state voltammetry at platinum and mercury film microelectrodes, and conductance measurements. It was found that for concentrations of polymer less than 1.5%, the diffusion coefficient of uncharged probes does not differ significantly from that observed in aqueous solutions without a polymeric network. For the probe cation, strong electrostatic interactions were observed between Tl(+) and anionic polymeric networks; those interactions resulted in a significant decrease in the diffusivity of Tl(+) cations. Experimental data for Tl(+) transport in sodium polyacrylate gels were compared with predictions of Manning's theory for polyelectrolyte solutions. Electrostatic interactions between Tl(+) and anionic polyacrylate three dimensional gel network were found stronger than those predicted for solutions of an equivalent polyelectrolyte. Theoretical expressions for conductivity as a function of poly(acrylic acid) neutralization degree were developed based on Manning's line charge model.